The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a semiconductor structure including a pair of semiconductor fins located on a punch-through stop base structure having concave outermost sidewalls. The present application also provides a method of forming such a semiconductor structure.
For more than three decades, the continued miniaturization of metal oxide semiconductor field effect transistors (MOSFETs) has driven the worldwide semiconductor industry. Various showstoppers to continued scaling have been predicated for decades, but a history of innovation has sustained Moore's Law in spite of many challenges. However, there are growing signs today that metal oxide semiconductor transistors are beginning to reach their traditional scaling limits. Since it has become increasingly difficult to improve MOSFETs and therefore complementary metal oxide semiconductor (CMOS) performance through continued scaling, further methods for improving performance in addition to scaling have become critical.
The use of non-planar semiconductor devices such as, for example, semiconductor fin field effect transistors (FinFETs) is the next step in the evolution of complementary metal oxide semiconductor (CMOS) devices. Semiconductor fin field effect transistors (FETs) can achieve higher drive currents with increasingly smaller dimensions as compared to conventional planar FETs.
For 10 nm technology and beyond, source-drain leakage current may become a challenge for bulk FinFET electrostatics. Punch-through stop (PTS) doping can be implemented to form sub-Fin PTS structures to reduce such leakage current. However, traditional direct ion implantation processes currently employed in forming sub-fin PTS structures cause Fin crystalline damage which, in turn, leads to unwanted defects in the channel region of the resultant FinFET device. There is thus a need for providing semiconductor structure containing sub-fin PTS structures in which crystalline damage is circumvented.